水平液化场地土表位移简化理论解答

水平液化场地地表往返位移的求解是基础和地下工程抗震设计的迫切需求。利用双层模型模拟实际水平场地,提出了可考虑液化层存在下的土表位移简化计算方法并给出频域理论解答,同时采用逐循环累计方法给出水平场地任意荷载下土表位移时域解答。采用适于水平场地孔压增量模型,并逐循环修正土层模量,模拟液化引起的土层的非线性过程。振动台试验结果和提出棋型的计算结果吻合,验证了所提方法能够反映土体液化对土表位移影响的基本过程。提出的方法和解答物理意义明确,可代表土体液化对土表位移影响的基本形态,并可用于频域及时域的无量纲分析。

A simplified theoretical solution of displacement in horizontal liquefiable soil strata

A cyclic horizontal displacement solution of subsoil is of great concern in aseismic design of foundations and underground structures. Herein a double-layer model is adopted to simulate horizontal strata and to provide a theoretical simplified displacement solution in frequency domain which considers an existing liquefiable soil layer. Meanwhile, the relevant displacement of subsoil under arbitrary loading in time domain is also presented by the cycle-by-cycle method. Using a proper porewater pressure incremental model for horizontal soil strata, the moduli of subsoil is updated cycle by cycle to simulate the nonlinear process of subsoil caused by liquefaction. The results of shaking table test are consistent with the calculated results. It is shown that the method proposed can describe the process of liquefaction fundamental influence on subsoil displacement. The proposed method which is of clear physical meaning can represent the basic model of influence of liquefaction on subsoil displacement; and it can be used for non-dimensional analysis in time and frequency domains.